This invention relates to new and improved means and methods for feeding pulp refiners, particularly double disc refiners.
An inherent and ever continuing problem in the operation of refiners, particularly disc refiners, has been the steam created within the refiner during the refining procedure. The material being refined either embodies or is entrained in a significant amount of liquid. This is a source of a great amount of steam as the electrical energy applied to the refining process is converted to heat. The steam so developed creates a blow back condition which usually interferes with the infeed of the material to be refined, to the extent that the feeding is sometimes blocked. In any event this blow back condition produces variations in the load on the motors which drive the refining elements and this adversely affects stock quality. The creation and holding of the steam within the refiner in excess amounts can itself have the same effect. The problem is so serious that there have been many, many solutions offered in this respect, some feasible for certain applications but none of which really solve the basic problem. Such solutions as have been proposed which are pertinent to an understanding of the present invention are evidenced in the following patents and publication:
U.S. Pat. Nos. 4,059,237; 3,845,910; 3,441,227; 1,795,603; 2,561,043 PA1 French Pat. No. 2,183,928 PA1 British Pat. No. 931,929 PA1 German (Offenlegungsschrift) 24 42 627
The solution of none of the noted patents provide benefits equal to those unexpected results which stem from use of the features of the present invention.
The prior art practice has not only affected quality of the refined product when the noted problem has been encountered but has resulted also in a reduction in the quantity of the refined product per unit time. As will be obvious, this has serious economical overtones and such overtones have increased the demand for solution of the problem.
There has been one more pertinent patent that has issued from an application previously co-pending with the present application. This U.S. Pat. is that of Engall, No. 4,132,366 dated Jan. 2, 1979. It reveals an approach to the problems above enumerated pertinent to that forming the subject matter of this case but the tack thereof is different and does not envision or embody distinctive features of the present invention as hereinafter disclosed and set forth in the appended claims.